The HIV epidemic continues to result in approximately 2 million new infections globally each year, with approximately 50,000 infections in the United States annually. Within the United States, approximately 63% of new HIV infections occur among men who have sex with men (MSM). Although behavioral interventions have demonstrated modest efficacy in reducing self-reported sexual risk-taking, they have been less effective in reducing HIV/STI incidence. Improved behavioral HIV prevention interventions and better intervention targeting are needed. The proposed project is designed to examine the association between delay discounting (DD) and condomless anal intercourse (CAI) in MSM. DD refers to the tendency of individuals to prefer smaller, immediate consequences or rewards over larger, delayed consequences or rewards. With respect to sexual behavior, a choice to have sex without a condom when one is not available could be conceptualized as a smaller, immediately available reward compared to the choice to wait until a condom is available, which could be conceptualized as the larger, delayed reward of potential sexually transmitted disease avoidance. If DD is found to be associated with CAI, then that association could form the basis for development of new behavioral interventions designed to reduce sexual risk-taking and HIV/STI incidence. It might also be a valuable tool to identify men most in need of HIV prevention intervention. DD will be measured in two ways in the proposed study. First, monetary discounting will be measured using the Monetary Choice Questionnaire (MCQ). The MCQ presents a series of choices between small, immediately available amounts of money and larger, delayed amounts of money. A respondent's pattern of preferences is used to determine the degree to which he discounts money available at a delay. Second, sex-specific DD will be measured using the Sexual Discounting Task (SDT). In this task, respondents indicate a preference between immediate sex without a condom and sex at a specified delay with a condom. The pattern of responding is used to determine the degree to which the respondent discounts sexual activity (i.e., willingness to wait). This project has three aims. For the first two aims, an Internet-based survey will be administered to MSM to obtain demographic information, recent sexual behavior history, and monetary and sexual discounting data. Aim 1 is to assess the association between monetary DD, sexual DD, and CAI and to examine if the association is modified by age. Aim 2 is to test the hypothesis that monetary and sexual DD are associated with CAI via direct and indirect pathways using structural equation modeling. In Aim 3, participants in an ongoing, NIDA-funded cohort study of HIV-negative, young, black/African-American MSM in Atlanta, Georgia, will complete the MCQ and SDT at baseline. Aim 3 is to assess the causal association between CAI and DD using longitudinal data analysis. To the extent that DD is found to be associated with risky sexual behavior, it has the potential to be a behavioral target of HIV prevention interventions for MSM and a tool to identify men most at risk of engaging in risky sexual behavior.